Filter.



Patented Apr. 1, 1913.

d 44 WM.

?Mu /%gaze F. P. J. GRENET.

PILTEB.

APPLIOATIOE I'ILED JULY 26, 1811.

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UNITED STATES PATENT OFFICE.

.FBANCSQUE PIERRE J' ACQUES GRENET bF BELLEVUE, FRANCE, ASSIGNOR TO SOCIT ANONYME DU FILTRE CHAMBERLAND SYSTEME PASTEUR, OF PARIS, FRANCE;

FILTER.

To all whom e' t may' concem Be it known that I, FRANCISQUE PIERRE.

- useful Improvements in Filters, of which the following is a specification.

This invention relates to filters and filtering apparatus and has for its object to provide improved means for rendering the filtering substance employed in apparatus of this description more eflicient in operation and less liable 'to become defective owing to long and continual use.

The filtering substance hitherto em loyed, whether composed of porcelain, inf sorial earth, asbestos, charcoal, cellulose or other material, after being in use for a certain length of time, is open to the disdvantage that the continual passage of the liquid not only leaves a deposit upon the surface of the substance, but the particles of impure matter which it is' desired to remove, penetrate below the surface of the substance, filling up the pores of the substance and thus rendering it less eflicient. Although it is possible to temporarily improve the operation of the filter by wiping or otherwise cleaning the surface of the filtering substance, the cleansing process in many cases further reducesthe efliciency of the filter by increasing the density of the obstructions' below the surface of the subst-ance.

According to this invention the above disadvantages are overcome by forming on the surface of the filtering substance a protecting covering which is in itself capable of Operating as a filtering medium and permits of ready cleansing either superficially or otherwise, so that the properties of the filtering substance are maintained for an indefinite period of time.

As is well known collodion obtained by dissolution of nitro-cellulose in a mixture of alcohol and ether or in acetone or other suitable liquid is up to a certain thickness permeable to liquids and it is this substance which is preferably employed in carrying this invention into practice. As, however, collodion is not in itself capable of resisting a high degree of pressure, it is applied in a' coating of suitable thickness to the filtering mantle or substanca constituting the filtering medium, thus forming a struc- Specification of !Letters Patet.

'exposed to the air at ordinary temperatures,

dries up and loses its filtering properties Patented Apr. 1, 1913.

Application filed July 26, 1911. Serial No, 640313. i

and that when a certain degree of dryness has been reached, the film or coating of collodion Cracks and subsequently peels off from the body to which it has been attached. It is therefore necessary to avoid deterioration in the filtering property of the collodion to maintain it in a more or less moist condition, which will prevent it from cracking and peeling off from the surface to which it has been applied.

The filtering mantle or substance is preferably coated with collodion by immersing the body in a collodion bath or otherwise cover-ing it with collodion of a suitable thickness and subsequently immer-sing the filtering body thus coated in a bath of diluted alcohol and then in water. To prevent desiccation of the collodion it is necessary that it should be brought to a permanently hygrometric state and for this purpose the filtering body is immersed in a bath of glycerin and water, or of honey or other suitable substanca A film of collodion possessing filtering properties can also be obtained by incorporating with the collodion a substance such as lucose elatin tannin and other saline for a cbnsiderable time, not ben in use; but when such a course is rendered esirable, the filtering medium maybe removed and placed under a jet of Water,` or it may be cleansed by means of a pad of medicated cotton wool or otherantiseptic 'passedlightly over the surface.

A filtermantle embodying thepresent inyention, is shown in the accompanying drawn i represents the porous body and B the coa'ting or film of collodion applied thereto. It is obvious, however, that the invention may find expression in a variety of Constructional forms.

Having now particularly described and ascertained the nature of my said invention and in 'What manner the same is to be performed, I declare that what I claim is:

1. A filter comprising a solid filtering medimncovered wth a coating of collodion, which is filtering. v v

2. A filter comprising a film of collodion adapted to pass liquid therethrough.

3. A filter comprising a film of collodion adapted to pass liquid therethrough and a support for said film.

4:. A filter comprising a porous body covered with a coating of collodion rendered' hygrometric after the coating has been applied.

5. The process of manufacturing filtering mediums comprising immersing a solid filtering body in normal collodion and then in a bath of diluted alcohol, and in water.

6. The process of manufacturing filtering mediums comprisngimmersing a solid filtering body in normal collodion, in which is` incorporated glucose, gelatin, tannin or other saline, mineral or Organic substance, soluble in alcohol, ether and water.

7 The process of manufacturing filtering apparatus comprising de ositing a coatin of collodion upon a solid lter structure an subsequently rendering -it hygrometric by immersing the solid filtering structure in a bath of glycerin 'and water.

8. The process of manufacturing filtering apparatus comprising de ositing a coatin'g of collodion upon a solid lter structure and subsequently rendering it hygrometric by immersing the solid filtering structure in a bath of glycrin and Water with the addition of an antiseptic.

9. The process of manufacturing filtering mediums comprising depositing a coating of collodion upon a filtering substance or structure, and subsequently rendering the coating hygrometric, substantially as described.

10. Filter-ing apparatus comprising asolid structure provided with an adhesive coating of collodion, substantially as and for the purpose specified.

In witness whereof, I have hereunto signed my name in the presence of two subscrbing witnesses.

FRANCISQUE PIEREE JACQUES GRENET.

Witnes'ses:

H. C. CoxE, REN BARDY. 

